docs(all): standardizes and adds return types, also some param fixes

src/plugins/themeable-browser.ts

@@ -183,6 +183,7 @@ export class ThemeableBrowser {
   /**
    * Injects JavaScript code into the browser window.
    * @param script    Details of the script to run, specifying either a file or code key.
+   * @returns {Promise<any>}
    */
   @CordovaInstance()
   executeScript(script: {file?: string, code?: string}): Promise<any> {return; }
@@ -190,6 +191,7 @@ export class ThemeableBrowser {
   /**
    * Injects CSS into the browser window.
    * @param css       Details of the script to run, specifying either a file or code key.
+   * @returns {Promise<any>}
    */
   @CordovaInstance()
   insertCss(css: {file?: string, code?: string}): Promise<any> {return; }
@@ -198,7 +200,7 @@ export class ThemeableBrowser {
    * A method that allows you to listen to events happening in the browser.
    * Available events are: `ThemeableBrowserError`, `ThemeableBrowserWarning`, `critical`, `loadfail`, `unexpected`, `undefined`
    * @param event Event name
-   * @returns {Observable<any>} Returns back an observable that will listen to the event on subscribe, and will stop listening to the event on unsubscribe.
+   * @returns {Observable<InAppBrowserEvent>} Returns back an observable that will listen to the event on subscribe, and will stop listening to the event on unsubscribe.
    */
   on(event: string): Observable<InAppBrowserEvent> {
     return new Observable<InAppBrowserEvent>((observer) => {